Distillation of carbonaceous solids



July 17, 1951 L. c. HuFF DISTILLATION OF CARBONCEOUS SOLIDS 2Sheets-Sheet l Filed March 22,` 1946 July 17, 1951 L. c. HUFFDISTILLATION oF cARBoNAcEoUs soLIDs 2 Sheets-Sheet 2 Filed March 22,1945 Patented July 17, 1951 2,560,767 DISTILLATION F CARBONACEOUS SOLIDSLyman C. Huff, Evanston,

Ill., assignor to Universal Oil Products Company, Chicago, Ill., a

corporation of Delaware Application March 22, 1946, Serial No. 656,470

6 Claims. l

This invention relates to an improved method and apparatus fordistilling oil shales, tar sands, coal or other carbonaceous solids.More particularly the invention relates to an improved type of retortand means of direct contact between the bed of solids and heatingmediums such that the apparatus will operate eiiiciently and in a exiblemanner to pyrolytically convert the solids into hydrocarbon conversionproducts.

Broadly, my invention provides a unitary vertical retort having a seriesof contact zones arranged in vertical alignment whereby a moving bed ofcrushed hydrocarbonaceous solid material. such as oil shale, maycontinuously move by gravity from top to bottom through the variouscontact zones within the retort, with relatively all of the volatilematerials being obtained from the solid material, and spent shale ashbeing removed from the lower end of the retort. In each of the zones,the bed of crushed oil shale, or other material, takes the form of arelatively shallow bed lying on a sloping grate at its angle of repose.such that the bed is of a uniform thickness in each of the contact zonesthroughout the retort from top to bottom. Partitioning members, grates,gas inlets and outlets are so arranged that the heating mediums andvapors will pass directly through each of the moving shallow beds indirect contact with the crushed solid material. One of the importantadvantages in the improved retort which makes possible the improvedmethod of operation, is the provision for moving or oscillating thegrates on which the shale bed reposes in each of the process zones suchthat the bed is agitated and prevented from coking and clinkering.Adjustment means is also provided for varying the slope of each grateand accommodating the mov- 'ing grate to the angle of repose for theparticular material Within a given zone.

Oil shales are generally referred to as being of twr` different types,that is non-coking shales and coking shales. The latter type is diicultto process as it must be retorted in a manner to prevent clinkering ofthe entire mass as it is heated. However, a vcoking shale may be readilyprocessed in the retort of this invention by reason of the continuouslyoscillating grates which keeps the material moving and agitated orbroken up such that clinkering is substantially prevented.

It is an object of this invention to provide a method whereby largequantities of shale may be processed continuously in an economicalmanner.

Another object of the invention is to provide an apparatus and methodoperation which will accommodate itself to any type of crushed solidhydrocarbonaceous material, including oil shales of either thenon-coking or coking types.

Still another object of the invention is to provide a retort having aplurality of contact zones or chambers in alignment, such that the solidmaterial may proceed by gravity downwardly from one zone to the next,and is arranged so that distillation may be carried on rst in a lowtemperature zone and then passed to zones of higher temperature for morecomplete distillation. The volatile products are thus removed from thisimproved system, without being subjected to highly destructivetemperatures usually encountered in other methods and apparatus forprocessing oil shales.

An important advantage of this invention is that the shale bed iscontacted directly while in a relatively uniform and shallow bed. It hasbeen found that retorts employing indirect heating means are expensiveto operate and that it is economically desirable to obtain directcontact between heating medium and the solids, such as provided by theapparatus and method of operation comprising this invention. Aparticular advantage has also been found in the arrangement of this newretort, whereby a plurality of contact zones are aligned one above theother and are substantially separated so that different contactoperations are simultaneously and continuously carried out in each ofthe zones on a relatively uniform ribbon like moving bed of thehydrocarbonaceous material.

Other advantages will be apparent upon reference to the accompanyingdrawings and the following description thereof together with explanationof the processing operations which are ermployc'd in distilling the bedof hydrocarbonaceous soli Figure 1 of the drawing shows a sectionalelevation view through one form of the improved distilling retort.

Figure 2 ofthe drawing shows an enlarged view through one of the movableand adjustable grates on which the crushed solids bed is supported.

Figure 3 of the drawing shows a diagrammatic view of a more elaborateform of the improved retort and accompanying apparatus and conduitsemployed in processing solid carbonaceous material to obtain valuablehydrocarbon conversion products therefrom.

Referring now to Figure 1 of the drawing. a vertical rectangular retorthousing I is shown in cross-sectional elevation. The housing l lspreferably made of steel or alloy construction that is suitable toaccommodate the temperature conditions prevailing throughout the heightof the retort. A plurality of contact chambers are disposed verticallywithin the housing I such that a solid carbonaceous material passessuccessively from one to the other and from top to bottom. The variouscontact chambers or zones within the retort, from top to bottom may beidentified as follows; a crushed shale hopper 2, a pre-heating zone 3,an initial distilling zone 4. a nal distillation zone 5, a burning zone6, a llrst cooling zone 1 and a nal cooling zone 8. The crushed oilshale or other so'lid hydrocarbonaceous material .is carried to the topof retort I and discharged into the hopper 2 by means of a conveyor orelevator 9. The shale then descends by gravity through each of thezones, being aided in its descent by oscillating grate l0. In the hightemperature zones, such as the burning zone, a refractory lining I' canbe used to protect the interior of the housing I.

Figure 2 of the drawing illustrates one form of the moving andadjustable supporting grate I0, which comprises primarily a steel frameand a series of tuyre plates II. The tuyre plates II are mounted andarranged in an overlapping manner such that the descending bed ofcrushed solid material will not fall through the grate. However, thetuyres II are so constructed that gases and vapors will be equallydistributed to the shale bed, through spaces I2, between each of theoverlapping plates. The upper end of the frame of the grate I is pivotedon a bar I3, while at the lower end a rotating bar` I4, having cams I5,will serve to move the end of theentire grate in a slight up and downmovement. A slotted opening I6, in the side wall of the retort, having acover plate and adjustment means not shown, makes it possible to varythe angle of the grate I0 to parallel the angle of repose of the shalebed in each of the contact chambers. It is evident, that by properpreliminary adjustment, the moving grate may be made to support thedescending shale in a bed of relatively even thickness and therebyattain substantially uniform conversion throughout the entire length ofthe bed in each contact zone. The mechanical means and method ofrotating the lower cam shaft I4 is not illustrated, as the means ofrotation may be conventional and may be provided in any desired manner.It is however, within the scope of this invention to have varying sizesand types of cams and to thereby vary the frequency and the amount ofmovement or agitation of the bed in any one of the contact zones. Bailiemembers II are mounted in front of the various gas inlets, to each ofthe `contact zones, and are found desirable to prevent directchannelling of the contact medium through a conned portion of the grateand the supported shale bed.

Referring again to Figure 1 of the drawing, the descending shale bed iscontacted by hot air, within the pre-heating zone 3, with the heated airstream being admitted by way of conduit I8 and discharged through outletconduit or stack I9. The shale is preferably preheated within thiscontact zone 3 to a temperature of the order of 500 F. However,relatively little volatile matter is removed at this temperature and thegases are normally allowed to be discharged to the atmosphere by way ofthe stack I9. A heated recycled stream of a portion of the uncondensedconversion product is employed, with or without an auxiliary supply ofhigh temperature super-heated steam, to eilect a rst distillation inzone 4. 'I'he recycled fluid medium enters by way oi' conduit 20, whilesteam is charged by way of line 2l having control valve 22, and thedistillation products are carried by way of conduit 23 to suitableseparating and fractionating equipment, not shown.

The moving bed of crushed material, following the first distillation inzone 4, is subjected to a higher temperature and final distillationwithin zone 5, the heating medium therein being hot l combustion gasesreceived directly from the burning zone 6. Air is blown to zone 6 by wayof a blower 24 and conduit 25 such that relatively complete removal ofall volatile or combustible material is elected therein. Combustiongases at a temperature of approximately 1500 F. are passed from theshale bed of burning zone 6 to the iinal distillation zone 5 and aredischarged from the retort by way of outlet conduit 26. The combustiongases thus carry with them the distillation and conversion products fromthe pyrolytic contact within zone 5, and the combined conversionproducts are passed by way of conduit 26 Ato suitable separating andfractionating equipment, not shown. A first cooling operation for thehot spent shale is effected in zone l wherein a recycled stream ofuncondensed conversion products from the separating step are charged byway of line 21 having control valve 28. In addition an auxiliary Supplyof oxygen containing gas, such as steam may be charged by way of line 29having valve 30. The heated recycle gas stream leaves this rst coolingzone 1 at a temperature of approximately l300 F. and passes by way ofconduit 20 to the initial distillation zone 4, to eiect a firstdistillation, as previously noted in the description. In the nal coolingzone 8, air from blower 3| and the inlet conduit 32 is passed throughthe spent shale bed prior to the discharge of the latter from the retortI through outlet gate 33. The air stream thus used to cool the spentshale, absorbs heat therefrom and is discharged from zone 8 at atemperature approximating 600 F. being carried by way of conduit I8 tothe preheating zone 3, where as previously noted the heated air fromline I8 is used to bring the incoming shale bed up to an initialtemperatureV of 500-550 F. The spent shale from the lower end of theretort I is passed on to a conveyor 34,A in order that it may becontinuously carried away from the retort and disposed of.

In a retort of the type disclosed and by means of the improved method ofcontact and operation which has been described, large quantities of oilshale may be continuously processed. For example, with a 10 ft. by 20ft. rectangular retort. and a rate of movement through the retort beingadjusted so that the shale bed is contacted for approximately one hourin each zone, then some 300 tons per day of shale may be subjected tocomplete conversion. In order to attain optimum operating conditions,the shale or carbonaceous material should be crushed to a size ofapproximately 1/2 to 1 1/2 inches in size. Shale larger than 1 1/2inches will require a longer period for the heat to penetrate to thecenter of the lumps or pieces and the capacity of the retort will haveto be slowed down accordingly.

Referring now to Figure 3 of the drawing a more elaborate form of retortis shown in combination with accompanying process equipment employed toobtain both hydrocarbon distillates and producer gas from shale or othersolid cai'- bonaceous material. A plurality of contact zones are spacedin vertical alignment within the retort 40 and from top to bottom may beidentied as follows; a hopper 4|, a pre-heating zone 42, a rstdistillation zone 43, a second distillation zone 44, a purging zone 45,a burning zone 46, a gas producing zone 41, a first cooling zone 48 anda second cooling zone 49.

Crushed material is lifted to the top of the retort 40 by means of aconveyor or elevator 50 and is then dumped into the hopper 4|. The shalemoves downwardly in a relatively uniform bed through each of the contactzones over moving grates 9, which may be constructed and operated asnoted in connection with Figure 2 of the drawing. Shale ash iscontinuously removed from the lower end of the retort through gate 5| toa belt conveyor 52 which carries the spent material to a disposal zone,not shown. Each of the vertically aligned zones are separated one fromanother by partition plates 53 which may be constructed of steel oralloy suitable for the temperature conditions encountered.

Air is blown through the bed of spent shale in a second cooling zone 49by means of air blower 80 and conduit 8| in order to effect a finalcooling of the spent material prior to its discharge from the retort andto provide heated air, at approximately 600 F., which is channeled byway of conduit 54 to the upper pre-heating zone 42. The shale movingthrough zone 42 is thus heated to a temperature of approximately 500 F.At thisv temperature, little or no volatile matter is removed from thesolids and the heating medium may be discharged through the outletconduit or vent stack 55. The pre-heated shale bed then descends to thefirst distillation zone 43, wherein a hot fluid medium, comprising arecycled uncondensed fraction of the conversion products, is used toeffect the removal of the more volatile products within this zone at atemperature of the order of '100 F. The conversion products from thisrst distillation zone 43 are passed by way of line 56 to a fractionator51. The light fractions irom fractionator 51 are passed by way of line58 through a suitable condenser 59 and line 60 to a receiver tank 6| Theuncondensed fractions from receiver 6| are withdrawn through line 62 byexhauster pump 63 and passed to line 64 having a valve 64', beingrecycled to the retort by way of gas blower 65 and conduit 66. Anyexcess quantities of uncondensed gases may be passed by way of line 61,having control valve 68 and 69, to a gas holding vessel 10. The recycledgas passing to zone 48 of the retort effects a first cooling of theoxidized shale bed and thereby acquires a temperature of approximately1000 F. The heated recycled stream is then passed from zone 48 by way ofconduit 1| to the first distillation zone 43, as previously noted. Thecondensed hydrocarbon fraction collected within the receiver 6| may bepassed to storage or to further treating equipment by way of line 12,pump 13 and line 14. A portion of this condensed fraction may be usedfor recycle to the fractionator 51, passing by way of line 15 havingvalve 16. The quantity of condensed fraction being removedfrom receiver6| will be controlled by a liquid level controller 11 and automaticcontrol valve 18 in line 14.

The shale bed, lollowing the first distillation in contact zone 43,passes to a second distillation zone 44 wherein more completedistillation is effected by a hot stream of producer gas entering by wayof conduit 19 from the lower gas producing zone 41. Conversion productsfrom zone 44 are passed by way of line 82 to a column 83 for separationinto light gaseous fractions and heavy liquid fractions. The lighthydrocarbon fractions are passed by way of line 84 to a. condenser 85and therefrom by line 86 to a receiver 81. The uncondenser gas fractionsfrom this conversion step are withdrawn from receiver 81 by way of line88, exhauster pump 89, and may be passed through line having a valve 9|to gas storage or it may be recycled to zone 41 of the retort 40. Thegas blower 92 receives the uncondensed recycled gas stream anddischarges it by way of line 93 to the gas producing zone 41.

fractionating ducer gas which will be at a temperature of approximately1350 F. The producer gas stream 1s passed by way of conduit 19 to thesecond distillation zone 44 to effect a high temperature conversiontherein as has been previously noted. Excess quantities of uncondensedgases from the second stage distillation and fractionation step may bewithdrawn from the line 90 to a gas holder 94 by Way of line 95 havingvalve 96. The condensed fractions from the receiver 81 may also bepassed to storage or to further treating equipfractionator 63 by way ofline |00 having valve |0I. The rate of flow to storage, through line 99,will be controlled by a liquid lleiel controller |02 and automaticcontrol valve The descending shale bed having substantially all of itsvolatile material removed in the second distillation zone 44 is thenpassed to the purging zone 45 wherein it is purged with a relativelyinert gas, flue gas, or preferably superheated steam, to effect thefurther removal of any remaining volatile matter as well as drive offany gaseous materials that have formed during the distillationoperation. The purging medium is charged by way of line |5| having valve|52 to the zone 45. The products from the purging zone are passed by wayof line |04 to fractionator |05 to be suitably separated andfractionated. The light fractions from fractionator |05 are passed byway of line |06, condenser |01 and line |08 to a receiver tank I 09. Theuncondensed gases from receiver |09 are passed to the gas holding tank10 by way of line H0, exhauster pump line ||2 and line 61. In analternate method of operation, a portion of the uncondensed gases fromreceiver |09 may be passed by way of line ||2 and line 61 to line 64such that the gases will be recycled to the retort by blower 65.

Following the purging operation in zone 45, the shale bed passes to theburning zone 4G wherein the bed is subjected to relatively completeoxidation and thereby increased in temperature to approximately 1550 F.Air is charged to zone 46 by way of air intake line |53 having controlvalve |54, air blower ||3 and conduit ||4 such that substantiallycomplete oxidation of all carbonaceous and volatile matter isaccomplished as the shale passes therethrough. To provide a control forthe amount of oxygen and extent of burning in the zone 46, a flue gasstream is mixed with the air stream. This 4flue gas stream is recycledto the retort by way of line |55 having control valve |56. The resultingcombustion or flue gases from zone 46 are withdrawn through a waste heatboiler II5, by way of conduit H6, and are discharged therefrom throughconduit I| 1,

7 gas blower ||8 and vent stack H8. The stack ||9 has a valve ||9 whichmay be adjusted, to permit a portion of the flue gas to pass to theburning zone 46, in admixture with air entering by way of conduit I |4.Steam is generated within the waste heat boiler ||5, feed water beingcharged by way of line |20 having valve |2l. The steam generated in thewaste heat boiler is collected in a steam drum |22 and withdrawntherefrom through line |23, passing through a steam pre-heating coil |24within the inlet end of the waste heat boiler ||5. Superheated steamfrom coil |24 passes to line |25 and then to both the purging zone 45and the gas producing zone 41, the superheated steam being passed to thefirst mentioned zone by way of line |25 having valve |21 and to thelatter zone by line |25 having valve |28. When the oxidation in zone 48has been only partial, the partially burned or oxidized shale passesfrom zone 46 to the gas producing zone 41 at a sufilciently hightemperature, approximately 1550 F., such that water-gas is produced bycontact with superheated steam and air which is charged thereto by line|25. Air is received and passed by way of line |51, having control valve|58, to the line |25 and to the gas producing zone 48. Producer gas maythus be produced in large quantities having a high B. t. u. value. In analternate operation, within the gas producing zone, oil may beintroduced with the superheated steam to produce a much higher B. t. u.producer gas. Oil may be charged from an external source through line|29 having valve |29' to combine with the steam within line |25, or itmay be received as a condensed 'fraction from fractionator 83, by way ofconnecting line |59 having valve |60.

It is also within the scope of the invention to recover selectednormally liquid fractions formed in the fractionators 51, 83 and |05 asnal products of the process. Line |30 having pump |3| may be employed towithdraw the liquid fraction from fractionator 51 and pass the recoveredmaterial by way of line |32 t a suitable storage tank. The liquidfraction from fractionator 83 may be withdrawn by way of line |33, pump|34 and line |35 having valve |36 to further treating equipment or tostorage. Likewise, the liquid fraction from fractionator may bewithdrawn through linef|31, pump |38, and line |39 having valve |40 tofurther treating or storage equipment.

As a means of further increasing the B. t. u.

' value of the producer gas in zone 41 a portion of the normally liquidfraction from fractionator |05 may be passed to a spray nozzle |4| abovethe bed of solids, within zone 41, by way of line |42 having controlvalve |43. In like manner, a portion of the liquid fraction fromfractionator 83 may be passed to a spray nozzle |44 within zone 41 byway of line |45, having valve |46, and line |35 connecting with thelower end of the fractionator.

In order to provide greater flexibility in the operation of the unitaline |41 having valve |48 is provided so that a portion of the recycleduncondensed gas from the first distillation zone may be passed eitheralone or in combination with uncondensed gas from the seconddistillation zone, to the gas producing zone 4'|. Also, line |49 havingvalve |50 is provided to connect between line 90 and line 64 such thatuncondensed gas from the second distillation zone may be passed, eitheralone or in combination with uncondensed gas from the first distillationzone,

to the rst cooling zone 48 within the retort 48.

Pressure control and pressure indicating devices are not illustrated inthe drawings, however, such devices are desirable and normally may beconnected with each of the contact chambers, such that the properoperating pressures and gas flows may be maintained throughout theretort.

It may be noted from the above description that this process provides aconvenient and economical method for continuously processing crushed oilshales or other types of carbonaceous solids in successively highertemperature conversion zones, without involving destructive distillationof the material. Also, an excess of heat will be available from theimproved process and apparatus which can be used to generate steam orelectrical energy.

While the term oil shale has been used in much of the above description,it should be understood that the use of this type of retort is notlimited to any one material, but is adaptable for use with any crushedhydrocarbonaceous material.

I claim as my invention:

l. A method for producing valuable hydrocarbon liquidsand gases fromhydrocarbonaceous solids which comprises maintaining an agitated anddescending bed of said solids in continuous travel through a series ofcontact zones within a retort, contacting said solids bed with a heatedgaseous meduim in a pre-heating zone, passing Said bed to a rstdistillation zone and contactingA with a second heated gaseous medium toeiect distillation of vaporous and gaseous products therefrom, passingsaid bed to a second distillation zone and contacting therein with athird heated gaseous medium to eiect a higher temperature distillationof vaporous products therefrom, passing said bed to a burning zone andcontacting therein with a gas containing free oxygen to' effectoxidation of combustible material therein, passing the hot oxidizedsolids bed to a hot gas producing zone and contacting said solids bedtherein with said third gaseous medium prior to passing it with absorbedheat to said second distillation zone, passing said solids bed to acooling z'one and contacting said bed therein with said second mentionedgaseous medium prior to passing it with absorbed heat to said firstdistillation zone, passing said solids bed to a final cooling zone andcontacting said bed therein with the first mentioned gaseous mediumprior to passing it with absorbed heat to said pre-heating zone.

2. A method for producing valuable hydrocarbon liquids and gases fromhydrocarbonaceous solids which comprises maintaining an agitated anddescending bed of said solids in continuous travel through aI series ofseparate superimposed contact zones, independently and adjustablyagitating said bed in each of said zones. contacting said solids bedwith a heated gaseous medium in a first distillation zone to effectpartial distillation of vaporous products therefrom, subjecting saidvaporous products to condensation and separation, contacting said solidsbed with a second heated gaseous medium in a second distillation zone toeiect a higher temperature distillation and removal of vaporous productstherefrom, subjecting said vaporous and gaseous products from saidsecond distillation zone to condensation and separation, passing saidsolids bed to a burning zone and contacting said bed therein with a gascontaining free oxygen to efthe hot solids bed from said burning zone toa cooling zone, returning regulated portions of un` condensed fractionsfrom rst said condensation and separation step to contact said solidsbed in said cooling zone, passing said recycled uncondensedl gass streamwith absorbed heat to said second distillation zone as said secondheated gaseous medium, returning regulated portions of uncondensedfractions from said second condensation and separation step to contactsaid solids bed in a second cooling zone and passing the last saidrecycled uncondensed gas stream with absorbed heat from said secondcooling zone to said first distillation zone as the first mentionedheated gaseous medium.

3. A method for producing valuable hydrocarbon liquids and gases fromhydrocarbonaceous solids which comprises maintaining an agitated anddescending bed of said solids in continuous travel through a series ofcontact zones within a retort, contacting said solids bed in apre-heating zone with a heated air stream, passing said solids bed fromsaidpre-heating zone to a rst distillation zone and contacting said bedtherein with a hot gaseous medium to effect a partial distillation ofvaporous products, passing said solids bed to a second distillation zoneand contacting saidA bed with hot combustion gases to eiect a morecomplete distillation, passing said solids bed from the seconddistillation zone to a burning zone and oxidizing said bed therein toeffect the removal of residual combustibles, passing combustion gasesfrom said burning zone directly to said second distillation zone,removing vaporous and gaseous products from each of said distillationzones and subjectlng said products to condensation and separation,passing said solids bed from said burning zone to a rst cooling zone,returning a regulated portion of uncondensed gases from said condensa- Ytion and separation step to said rst cooling zone and therein contactingsaid solids bed, passing the resulting gas stream from said firstcooling zone with absorbed heat therein to rst said distillation zone,passing said solids bed from the first cooling zone to a second coolingzone. contacting said solids bed in said second cooling zone with an airstream and passing said air with absorbed heat to said pre-heating zone.

4. A method for producing valuable hydrocar-A bon liquids and gases:from hydrocarbonaceous solids which comprises maintaining an agitatedand descending bed of said solids in continuous movement through aseries of contact zones within a retort, contacting said solids bed in apre-heating zone with a heated air stream, passing said solids bed to arst distillation zone and contacting therein with a hot gaseous mediumto eifect a partial distillation of vaporous products,passing saidsolids bed to a second distillation zone and therein contacting said bedwith a second hot gaseous medium to effect a more complete distillation,passing said solids bed to a purging zone and therein contacting saidbed with a third gaseous stream to effect removal of volatile andgaseous products, subjecting vaporous and gaseous products from saiddistillation zones and said purging zone to condensation. andseparation, passing said solids bed to a burning zone and thereinoxidizing said bed to i effect the removal of combustibles, passing theoxidized solids from said burning zone to a gas producing zone,returning a regulated portion of uncondensed gases from the seconddistillation zone to said gas producing zone and passing the resultinghot gases to said second distillation zone as said second gaseousmedium, passing Said solids from the gas producing zone to a rst coolingzone and contacting said solids therein with a regulated portion ofuncondensed gases separated from a. first distillation zone and passingthe resulting hot gases to said rst distillation zone as said gaseousmedium, passing solids from said rst cooling zone to a second coolingzone and contacting said solids therein with an air stream prior todischarging said solids from the retort and passing the resulting hotair stream from said second cooling zone to the preheating zone.

5. A retort for recovering valuable products from crushedhydrocarbonaceous solids which comprises an elongated Vertical housing,partitioning means dividing the housing into a series of at least sixcontact chambers aligned therein, an inlet for charging crushed solidsto the upper end of said retort, an outlet for discharging ash from thelower end of said retort, a fluid inlet and a fluid outlet to each ofsaid contact chambers, a conduit connecting the fluid outlet of thelowest contact chamber with the inlet to the upper contact chamber, aconduit connecting the next to the lowest contact chamber with the nextto the upper contact chamber and a conduit connecting the third fromlower `contact chamber with the third from the upper contact chamberwhereby heated iiuid mediums may be passed from the lower chambers tothe upper chambers. Y

REFERENCES CITED The following` references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 464,934 Dubbs Dec. 8, 18911,669,023 Runge May 8, 1928 1,669,024 Runge May 8, 1928 1,805,109 RungeMayl12, 1931 1,932,296 Trent Oct. 24, 1933 1,973,913 Sperr Sept. 18,1934 2,131,702 Berry Sept. 27, 1938 2,165,143 Karrick July 4, 19392,199,945 Archer May 7, 1940 2,406,509 Pilo Aug. 27, 1946 2,435,746Jones Feb. 10, 1948 FOREIGN PATENTS Number Country Date 638,595 FranceFeb. 21, 1928 291,475 Great Britain June 5, 1928 107,907 Australia July5, 1939

1. A METHOD FOR PRODUCING VALUABLE HYDROCARBON LIQUIDS AND GASES FROMHYDROCARBONACEOUS SOLIDS WHICH COMPRISES MAINTAINING AN AGITATED ANDDESCENDING BED OF SAID SOLIDS IN CONTINUOUS TRAVEL THROUGH A SERIES OFCONTACT ZONES WITHIN A RETORT, CONTACTING SAID SOLIDS BED WITH A HEATEDGASEOUS MEDIUM IN A PRE-HEATING ZONE, PASSING SAID BED TO A FIRSTDISTILLATION ZONE, AND CONTACTING WITH A SECOND HEATED GASEOUS MEDIUM TOEFFECT DISTILLATION OF VAPOROUS AND GASEOUS PRODUCTS THEREFROM, PASSINGSAID BED TO A SECOND DISTILLATION ZONE AND CONTACTING THEREIN WITH ATHIRD HEATED GASEOUS MEDIUM TO EFFECT A HIGHER TEMPERATURE DISTILLATIONOF VAPOROUS PRODUCTS THEREFROM, PASSING SAID BED TO A BURNING ZONE ANDCONTACTING THEREIN WITH A GAS CONTAINING FREE OXYGEN TO EFFEECTOXIDATION OF COMBUSTIBLE MATERIAL THEREIN, PASSING THE HOT OXIDIZEDSOLIDS BED TO A HOT GAS PRODUCING ZONE AND CONTACTING SAID SOLIDS BEDTHEREIN WITH SAID THIRD GASEOUS MEDIUM PRIOR TO PASSING IT WITH OBSORBEDHEAT TO SAID SECOND DISTILLATION ZONE, PASSING SAID SOLIDS BED TO ACOOLING ZONE AND CONTACTING SAID BED THEREIN WITH SAID SECOND MENTIONEDGASEOUS MEDIUM PRIOR TO PASSING IT WITH ABSORBED HEAT TO SAID FIRSTDISTILLATION ZONE, PASSING SAID SOLIDS BED TO A FINAL COOLING ZONE ANDCONTACTING SAID BED THEREIN WITH THE FIRST MENTIONED GASEOUS MEDIUMPRIOR TO PASSING IT WITH ABSORBED HEAT TO SAID PRE-HEATING ZONE.